Docking and drydocking members for externally insulated ships

ABSTRACT

An arrangement and construction for longitudinal extending bearing members disposed within the external insulation and attached to the hull of an externally insulated tanker for transferring impact loads such as may result from docking and drydocking through the insulation to the ship&#39;&#39;s structure. These longitudinal bearing members are made from a material such as balsa or hard rubber which possesses high compressive strength and are disposed along the sides and bottom of the ship&#39;&#39;s hull.

United States Patent [191 Iarossi et al.

[451 Jan. 15, 11974 [54] DOCKING AND DRYDOCKING MEMBERS 1,268,244 6/1918Henley 114/219 X O EXTERNALLY INSULATED SHIPS 2,890,880 6/1959 Hompe etal. 1 14/219 X [75] Inventors: Frank J. Iarossi, Middletown, N.J.;FOREIGN PATENTS OR APPLICATIONS Walter C. COWIGS, Cobhan, England1,062,454 12/1953 France 114/219 73 Ass' ee: Esso Re earch and En i 1compansy Linden N neermg Primary ExaminerGe0rge E. A. Halvosa lAssistant Examiner-Edward R. Kazenske 1 Filedi May 8, 1971Att0rneyManahan and Wohlers and F. Donald Paris [2]] App]. No.: 144,421

[57] ABSTRACT [52] CL 4/74 A 4/219 220/9 LG An arrangement andconstruction for longitudinal ex- [511 int. Cl 1163b 25/16 tendingbearing members disposed Within the external 5 Field of Search 1] 4/7273 79 74 R insulation and attached to the hull of an externally inll4/74A 219 220 65 R 65 LG sulated tanker for transferring impact loads suchas 9 A 14 1 may result from docking and drydocking through theinsulation to the ships structure. These longitudinal [56] ReferencesCited bearing members are made from a material such as balsa or hardrubber which possesses high compressive UNITED STATES PATENTS strengthand are disposed along the sides and bottom 3,283,734 ll/l966 Gormanll4/74 A of the ships 1 3,071,094 l/l963 Leroux 114/74 A 3.418.81512/1968 Kumazawa 114/219 X 6 Claims, 6 Drawing Figures Q2: Z6 26 a T/ TT/ T i DOCKING AND DRYDOCKING MEMBERS FOR EXTERNALLY INSULATED SHIPSCROSS-REFERENCE TO RELATED APPLICATIONS AND PATENTS The presentinvention has utility typically in an exter nally insulated ship such asdisclosed in the Gorman US. Pat. No. 3,283,734, assigned to the sameassignee to which the present application is'assigned and in US. Pat.application Ser. No. 144,422, filed May 18, l97l entitled GRID SYSTEMFOR EXTERNAL INSULA- TION, which discloses an arrangement andconstruction for securing external insulation to the ships hull andwhich latter application is assigned to the same assignee as that of thepresent application.

BACKGROUND OF THE INVENTION The present invention relates toliquid-carrying tankers and more particularly to an externally insulatedLNG tanker wherein the tanker may comprise a single shell internallystiffened both longitudinally and transversely with cargo sectionssubdivided into tank spaces by longitudinal and transverse bulkheadswith the tanker shell forming the outer tank boundary. One such typicalexternally insulated tanker is found in the aforementioned U.S. Pat. No.3,283,734, which discloses in a very broad sense only the use of plastickeel and bilge blocks and plastic or metal rub'rails disposed along thesides of the vessels. However, no details concerning the constructionand arrangement of such members is disclosed therein. 7

The present invention is directed towards providing a novel constructionand arrangement for docking and drydocking members for an externallyinsulated ship. Such members typically may comprise longitudinal bearingmembers made from a material, such as balsa or hard rubber or the like,possessing high compressive strength with the members being attached tothe hull of the externally insulated tanker so as to transfer impactloads through the insulation to the ships structure.

In a preferred embodiment a plurality of such bearing members would belongitudinally disposed along the sides and bottom of the vessel withthe side members extending beyond an outer protective covering disposedover the insulation and being spaced from slightly above the ballastwaterline to well above the full load waterline. In order to providecomplete protection during docking operations, three or more such sidemembers may be required. A typical construction might comprise the innerbearing member being the same thickness as the external insulation andbeing fixed to the hull preferably by means of bolting to flat barswelded to the ships hull. A silicon bedding compound may be used to fairand seal the member to the hull interface. It is important that thisinner member be comprised from material possessing good insulatingproperties and high compressive strength. Exemplary of such materialsare end grain balsa, oak, rubber composition, or a high density, closedcell foam. The outer protective covering or vapor barrier extends overthe insulation as well as the inner bearing member. There also isprovided an outer bearing member located external to the outer coveringand suitably fastened to the inner member. This outer member preferablyis of a lesser compressive strength than the inner bearing member sothat it will fail prior to the inner member being damaged. The outermember is fastened in such a manner that it can be easily removed andreplaced. A typical construction of inner and outermembers would be touse a high density balsa for the former and balsa of a slightly lowerdensity for the outer member. The balsa may be faced with a fiber glasslamina to provide better abrasion and permeability qualities. Thebearing members disposed along the ships bottom need only comprise aninner member designed to be flush with the external insulation andspaced to match the position of the drydock keel and bilge blocks.Various alternate embodiments are contemplated such as where the outerbearing member has an energy absorption type construction.

Thus, it is a primary object of the present invention to provide a novelconstruction and arrangement for an externally insulated tanker thatwill transfer impact loads through the insulation to the shipsstructure.

Having in mind this and various other objects that will be evident froman understanding of this disclosure, the present invention comprises thecombinations and arrangements as illustrated in the presently preferredembodiment of the invention, which is hereinafter set forth in suchdetail as to enable those skilled in the art readily to understand thefunction, operation, construction and advantages of it when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an outboard profile view ofan externally insulated tanker incorporating the present invention;

FIG. 2 is a bottom plan view of the externally insulated tanker of FIG.1;

FIG. 3 is an enlarged cross-sectional view taken substantially on theline 3-3 of FIGS. 1 and 2 illustrating an overall schematic arrangementof the present invention;

FIG. 4 is an enlarged detailed crosssectional view of a side bearingmember illustrating two different arrangements for securing the outerbearing member to the inner bearing member;

FIG. 5 illustrates an alternate embodiment to that shown in FIG. 4', and

FIG. 6 illustrates a detail constructional view of a bottom bearingmember constructed in accordance with the teachings of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Having reference to the drawingswherein the present invention is illustrated in FIG. I as embodied in anexternally insulated tanker typically having a nickel-steel plate hullat its midbody with reference being made to the aforementioned U.S.Gorman Pat. No. 3,283,734 for a more complete and detailed explanationthereof. Also, reference may be had to the aforementioned US. Pat.application Ser. No. 144,422 for details as to the securement of theexternal insulation to the ships hull.

FIGS. 1, 2 and 3 illustrate a tanker 10 including a cargo-carryingmidbody 12, a stern l4, and a forward hull portion or bow 16. The sternand the bow are fabricated conventionally from mild steel plate and mildsteel strengthening members. In accordance with the teachings of theaforementioned Gorman patent, the cargo-carrying midbody of the vesselmay be fabricated from a metal hull plating 18 that possesses thephysical and mechanical properties compatible with the particular cargoto be carried. Thus, a typical material for an LNG tanker might comprisenickel-steel containing substantially 9 percent nickel. Although notshown, the midbody 12 may be divided into a plurality of individualcargo hulls by means of transverse bulkheads and longitudinal bulkheads;but, in any event, the midbody is completely enveloped or cladexternally with a suitable external insulation 20. The externalinsulation 20 is provided with an outer protective covering 22 which isboth water-resistant and abrasion-resistant.

According to the present invention, there is provided a plurality oflongitudinally extending side bearing members 24 which extend slightlybeyond the outer covering 22 and are spaced slightly above the ballastwaterline WL,, to well above the full load waterline WL so that ineither condition adequate protection is provided to transfer any impactloads. Also there are provided a plurality of longitudinally extendingbearing members 26 along the bottom of the vessel which are constructedand arranged so as to terminate substantially flush with the outersurface of the insulation 20. As shown in FIG. 4, the side bearingmembers 24 comprise an inner bearing member 28 secured to the hullplating 18 by means of a plurality of nickel steel or stainless steelbolts 30, which extend perpendicular to the direction of the member 28,passing through a pair of vertically spaced flat bars 32 which arewelded as shown at 34 or otherwise suitably secured to the hull plating18. The bolt passes through predrilled holes in the inner bearing memberand is secured in place by conventional means. An alternate arrangementto the foregoing is to provide a single flat bar centrally disposed ofthe inner member 28 for receiving the bolt 30. In either alternative abedding compound 36 such as silicon is provided to fair and seal themember 28 to the hull interface. As shown, the flat bars 32 are disposedin substantially the same plane as the internal angle stiffeners 38 ofthe ships hull in order to provide the desired strength and rigidity forreceiving any impact. In the case of the side bearing members there isprovided an outer bearing member 40 which extends beyond the outercovering 22 (as shown in FIGS. 3 and 4) and is designed to be easilyremoved and replaced by means of fastening the member 40 to the innerbearing member 28 by means of a screw type fastener 42 which iscountersunk and filled in at the head by a suitable filler material 44such as silicon or the like. An alternate arrangement for securing theouter bearing member 40 to the inner member 28 is by means of a bolttype fastener 46 secured within the inner member 28 or threaded into anapertured plate member 48 operably secured with the inner member 28. Theouter member 40 is provided with an outer layer 50 such as reinforcedfiberglass lamina to provide for better abrasion and permeabilitycharacteristics. As illustrated, the outer member 40 is trapezoidal inshape; however, various other suitable shapes may be utilized.

FIG. 6 shows details of the bottom bearing members 26. These members arepositioned longitudinally and transversely such that they will contactthe docking blocks in a drydock. Since these members do not receive theimpact load that is applied to the side bearing members, there is nonecessity for employing an outer member such as 40 employed in the caseof the side bearing members. As in the case of the side bearing membersthe bottom members 26 each comprise an inner member 28 which is fastenedto the hull plating 18 in the same manner as is the inner bearing memberdiscussed in connection with the side members illustrated in FIG. 4.

An alternate arrangement and construction to that shown in FIG. 4 isillustrated in FIG. 5 wherein there is provided a partially hollowabsorption outer bearing member or fender 52. The member 52 istrapezoidal in shape and preferably is made of a reinforced rubbercomposition. This fender 52 is closed-ended and is provided throughoutits length with a central space 54 which may be filled with air or agaseous material to provide the necessary absorption qualities. As themember 52 receives an impact load, it compresses the fender 52 to highcompressive strength insulating blocks 58 disposed within and flush withthe outer surface of the insulation 20. The outer covering is disposedbetween the fender 52 and the insulation and the blocks. These blocks 58are secured to the hull plating 18 of the ship by means of L-shapednickel steel angle members 60 welded as shown at 34 to the hull. As inthe case of the flat bars 32 shown in FIG. 4, these members 60 aredisposed in substantially the same plane as the internal anglestiffeners 38 of the ships hull to provide for greater strength andrigidity to withstand impact loads.

It will be appreciated from the foregoing description that there hasbeen provided a novel and improved construction and arrangement fordocking and drydocking members for an externally insulated ship.However, it should be understood that the specific constructions andarrangements herein illustrated and described are intended to berepresentative of a preferred embodiment only, and that certain changesmay be made therein without departing from the clear teachings of thepresent disclosure. For example, the docking and drydocking bearingmembers although shown and described as each comprising a plurality ofsepa' rate members can comprise a single unitary member on either sideand on the bottom of the tanker. Accordingly, reference should be madeto the following appended claims in determining the full scope of theinvention.

Having thus set forth the nature of the invention, what is claimedherein is:'

I. An externally insulated tanker for the transportation of liquidcargoes comprising, in combination, a hull having forward and afterportions interconnected by a cargo-carrying midbody portion having sidesand a bottom, thermal insulation means secured to the exterior of saidhull, longitudinally extending bearing means disposed on each of saidsides and said bottom for transferring impact loads that may result fromthe docking and drydocking of said tanker through said externalinsulation to the tankers internal supporting structure, said sidebearing means being disposed so as to be operable both during full loadand ballast condition of said tanker, said side bearing means comprisingan inner bearing member and an outer bearing member secured to andhaving less compressive strength than said inner bearing member, sealantmeans disposed between said inner bearing member and said hull, andmeans for operably securing said inner bearing means to said hull.

2. An externally insulated tanker according to claim 1 wherein there areprovided a plurality of vertically spaced outward extending aperturedbars secured to the hull of said tanker, said bars being located at thetop and bottom of each of said inner bearing members,

and a bolt extending, through corresponding ones of said bearing membersand said bars for securing said member to said hull.

3. An externally insulated tanker according to claim 1 wherein saidouter member is constructed and arranged for the absorption of energysuch that as an impact load is applied thereto said outer member iscompressed thereby to transmit the impact load through the inner memberto the tankers internal structure.

4. An externally insulated tanker according to claim 3 wherein saidouter member comprises a partially hollow trapezoidal shapedclosed-ended configuration and said inner member comprises insulatingblocks disposed within said thermal insulation means.

5. An externally insulated tanker for the transportation of liquidcargoes comprising, in combination, a hull having forward and afterportions interconnected by a cargo-carrying midbody portion having sidesand a bottom, thermal insulation means secured to the exterior of saidcargo-carrying midbody, longitudinally extending bearing means disposedon each of said sides and said bottom for transferring impact loads thatmay result from the docking and drydocking of said tanker through saidexternal insulation to the tankers internal supporting structure, saidbearing means on said sides being disposed so as to be operable duringfull load and ballast condition of said tanker, said bearing means onsaid sides comprising an inner-bearing member and an outer-bearingmember secured to and having less compressive strength than saidinner-bearing member, sealant means disposed between said inner-bearingmember and said hull, means for operably securing said inner-bearingmeans to said hull, and a layer having abrasion-resistant andpermeability qualities disposed over said outer-bearing member.

6. An externally insulated tanker for the transportation of liquidcargoes comprising, in combination, a hull having forward and afterportions interconnected by a cargo-carrying midbody portion having sidesand a bottom, thermal insulation means secured to the exterior of saidcargo-carrying midbody, longitudinally extending bearing means disposedon each of said sides and said bottom for transferring impact loads thatmay result from the docking and drydocking of said tanker through saidexternal insulation of the tankcrs internal supporting structure, saidbearing means on said sides being disposed so as to be operable duringfull load and ballast condition of said tanker, said bearing means onsaid sides comprising an inner-bearing member and an outer-bearingmember secured to and having less compressive strength than saidinner-bearing member, sealant means disposed between said inner-bearingmember and said hull, means for operably securing said inner-bearingmeans to said hull, a plurality of vertically spaced outward extendingapertured bars secured to the hull of said tanker, said bars beinglocated at the top and bottom of each of said inner-bearing members, abolt extending through corresponding ones of said bearing members andsaid bars for securing said members to said hull, and internalstiffening members disposed in substantially horizontal alignment withsaid

1. An externally insulated tanker for the transportation of liquidcargoes comprising, in combination, a hull having forward and afterportions interconnected by a cargo-carrying midbody portion having sidesand a bottom, thermal insulation means secured to the exterior of saidhull, longitudinally extending bearing means disposed on each of saidsides and said bottom for transferring impact loads that may result fromthe docking and drydocking of said tanker through said externalinsulation to the tanker''s internal supporting structure, said sidebearing means being disposed so as to be operable both during full loadand ballast condition of said tanker, said side bearing means comprisingan inner bearing member and an outer bearing member secured to andhaving less compressive strength than said inner bearing member, sealantmeans disposed between said inner bearing member and said hull, andmeans for operably securing said inner bearing means to said hull.
 2. Anexternally insulated tanker according to claim 1 wherein there areprovided a plurality of vertically spaced outward extending aperturedbars secured to the hull of said tanker, said bars being located at thetop and bottom of each of said inner bearing members, and a boltextending through corresponding ones of said bearing members and saidbars for securing said member to said hull.
 3. An externally insulatedtanker according to claim 1 wherein said outer member is constructed andarranged for the absorption of energy such that as an impact load isapplied thereto said outer member is compressed thereby to transmit theimpact load through the inner member to the tanker''s internalstructure.
 4. An externally insulated tanker according to claim 3wherein said outer member comprises a partially hollow trapezoidalshaped closed-ended configuration and said inner member comprisesinsulating blocks disposed within said thermal insulation means.
 5. Anexternally insulated tanker for the transportation of liquid cargoescomprising, in combination, a hull having forward and after portionsinterconnected by a cargo-carrying midbody portion having sides and abottom, thermal insulation means secured to the exterior of saidcargo-carrying midbody, longitudinally extending bearing means disposedon each of said sides and said bottom for transferring impact loads thatmay result from the docking and drydocking of said tanker through saidexTernal insulation to the tanker''s internal supporting structure, saidbearing means on said sides being disposed so as to be operable duringfull load and ballast condition of said tanker, said bearing means onsaid sides comprising an inner-bearing member and an outer-bearingmember secured to and having less compressive strength than saidinner-bearing member, sealant means disposed between said inner-bearingmember and said hull, means for operably securing said inner-bearingmeans to said hull, and a layer having abrasion-resistant andpermeability qualities disposed over said outer-bearing member.
 6. Anexternally insulated tanker for the transportation of liquid cargoescomprising, in combination, a hull having forward and after portionsinterconnected by a cargo-carrying midbody portion having sides and abottom, thermal insulation means secured to the exterior of saidcargo-carrying midbody, longitudinally extending bearing means disposedon each of said sides and said bottom for transferring impact loads thatmay result from the docking and drydocking of said tanker through saidexternal insulation of the tanker''s internal supporting structure, saidbearing means on said sides being disposed so as to be operable duringfull load and ballast condition of said tanker, said bearing means onsaid sides comprising an inner-bearing member and an outer-bearingmember secured to and having less compressive strength than saidinner-bearing member, sealant means disposed between said inner-bearingmember and said hull, means for operably securing said inner-bearingmeans to said hull, a plurality of vertically spaced outward extendingapertured bars secured to the hull of said tanker, said bars beinglocated at the top and bottom of each of said inner-bearing members, abolt extending through corresponding ones of said bearing members andsaid bars for securing said members to said hull, and internalstiffening members disposed in substantially horizontal alignment withsaid bars.